Electrical circuit board technology is rapidly evolving toward smaller components and increased density of conductive traces. To keep pace, the connector interfaces must likewise be reduced in size and provide higher density points of electrical contact. At the same time, the precision of such connectors must be dramatically increased to insure the integrity of the resulting electrical connections. In fact, the spacing of traces and contact pad centers on contemporary circuit boards are now on the order of less than 0.020 inches. Such dimensions command precision-manufactured parts and accurate alignment features.
Great difficulty exists in manufacturing and assembling the necessary connector parts such as contact springs which can provide high-density points of contact while insuring reliable low-resistance electrical connections. The problems are compounded by additional design considerations such as minimizing the necessary insertion force.
U.S. Pat. Nos. 4,969,824 and 5,061,191 address the foregoing problems by employing a flexible printed circuit film strip with contact pads for electrically contacting an adjoining circuit board, and an underlying housing containing elongated coil springs which press the film strips and their contact pads against the appropriate point on the printed circuit board. The coil springs disclosed therein facilitate a high density array of stable low-resistance electrical contacts.
It would be greatly advantageous if comparable coil spring contacts could be incorporated in an edge-type connector. This would allow high-density interfacing of a circuit board to modular components such as a disk drive. However, this would additionally require an improved mechanical interface to accommodate slidable insertion of the circuit board over the coil springs.